Small Intestine & Mesentery

endoderm

Gut tube epithelium embryonic origin.

duodenum

Shortest part of small intestine.

ileum

Longest part of small intestine.

25cm

Length of duodenum

2.5m

Length of jejunum

3.5m

Length of ileum

duodenum

Part of the small intestine that is secondary retroperitoneal and lies in a c-shape around the pancreas

ileum

Part of small intestine that has the most encroaching fat in the surrounding mesentery.

1. L1 body

2. gastroduodenal artery

3. bile duct

4. porta vein

Anterolateral relations to D1.

first 2cm

Length of D1 that has mesentery.

gallbladder & quadrate lobe of liver

Posterior relations to D1.

5cm

Length of D1

jejunum

Which part of the small intestine has longer vasa recta with fewer arcades: ileum or jejunum?

small vessels that travel through the mesentery towards the gut tube

What a vasa recta of the intestines?

7-10cm

Length of D2.

liver & gallbladder

Structures that lie anterior to D2

1. L2 & L3

2. bile duct

3. pancreaticoduodenal vessels

4. inferior vena cava

Structures that lie to the left of D2

hilum of the right kidney & psoas major

Structures that lie posterior to D2

6-8cm

Length of D3

SMA & root of SI mesentery

Structures that lie anterior to D3

D3

Section of duodenum that crosses IVC, aorta, origin of inferior mesenteric artery right gonadal vessels & right ureter

D3

Section of duodenum found at the level of L3

5cm

Length of D4

coils of the jejunum

D4 lies posterior to which structures?

Just left of L3 up to the superior border of L2, 2cm to the left of the midline & aorta

Location of D4

inferior mesenteric vein & left ureter

Structures that lie to the left of D4.

suspensory ligament of Treitz

Skeletal muscle found at at the duodenojejunal junction

contracts to widen the angle of the duodenojejunal flexure and aid the movement of intestinal contents into the jejunum

Function of the suspensory ligament (of Treitz).

connects jejunum & ileum to the posterior abdominal wall; stores fat; conveys vessels & nerves to & from the gut

Function of the mesentery proper

from the duodenojejunal junction just to the left of the 2nd lumbar vertebra obliquely down to the ileocecal junction by the right sacroiliac joint

Location of the mesentery proper

gastroduodenal artery & superior pancreaticoduodenal artery

Vessels that supply D1 & D2

inferior pancreaticoduodenal artery

Vessels that supply D3 & D4

D1 & D2

Area of the small intestine supplied by the coeliac trunk

major duodenal papilla

Landmark for the change of blood supply from the coeliac trunk to the superior mesenteric artery

vasa recta from arcades formed by the anastomosis of 15-18 branches of the superior mesenteric artery

Vessels that supply the jejunum & ileum

long straight arteries arising from arterial arcades

What are vasa recta?

inferior pancreaticoduodenal artery

D2 & D4

Area supplies by this artery.

jejunal arteries

ileal arteries

vasa recta

jejunum

Part of the small intestine located in the upper left quadrant of the abdomen.

jejunum

Part of the small intestine that is associated with longer vasa recta & less arcades

ileum

Part of the small intestine that is associated with shorter vasa recta & more arcades

common hepatic artery

The gastroduodenal artery arises from which branch of the coeliac trunk?

pancreaticoduodenal & superior mesenteric nodes

Lymphatic drainage of the duodenum

superior mesenteric nodes

Lymphatic drainage of the jejunum & ileum

follow the arterial supply & drain into the hepatic portal vein

Venous drainage of the duodenum

superior mesenteric vein which unites with the splenic vein to form the hepatic portal vein

Venous drainage of the jejunum & ileum

vagus nerve

Parasympathetic supply to the duodenum

nerves from the coeliac plexus

Sympathetic supply to the duodenum

Lacteals

Lymphatic vessels in the centre of the intestinal villi responsible for absorbing dietary lipids

vagus nerve

Parasympathetic supply to the jejunum & ileum

nerves of the coeliac plexus & superior mesenteric plexus

Sympathetic supply to the jejunum & ileum